102069

Appears in sequences

• a(n) = 2*a(n-1) + a(n-2) - a(n-3) for n >= 3, starting with a(0) = 1, a(1) = 3, and a(2) = 6.at n=14A006356
• 3-wave sequence starting with 1, 1, 1.at n=30A038196
• Bottom line of 3-wave sequence A038196, also bisection of A006356.at n=7A038223
• Expansion of (1-x)/(1-2*x-x^2+x^3).at n=15A077998
• Expansion of x*(1-x)/(1-2*x-x^2+x^3).at n=16A106803
• Expansion of ( 1-x^3+x^4+x^5-x^8 ) / ( 1-2*x^3-x^6+x^9 ).at n=45A120771
• Expansion of ( 1-x^3+x^4+x^5-x^8 ) / ( 1-2*x^3-x^6+x^9 ).at n=50A120771
• Let i be in {1,2,3}, let r >= 0 be an integer and n=2*r+i-1. Then a(n)=a(2*r+i-1) gives the quantity of H_(7,1,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x=sqrt((2*cos(Pi/7))^2-1).at n=34A187068
• Let i be in {1,2,3}, let r >= 0 be an integer and n=2*r+i-1. Then a(n)=a(2*r+i-1) gives the quantity of H_(7,3,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x=sqrt((2*cos(Pi/7))^2-1).at n=32A187070
• T(n,k)=Number of nXk 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.at n=34A223999
• Number of 7 X n 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.at n=1A224005
• a(n) is the number of symmetrical linear hydrocarbon chains with n C-C bonds.at n=27A370377
• Expansion of x + 1/(-x - 1/(-x - 1/(-x + 1))).at n=14A373567